Johanness
122 lines
2.7 KiB
C++
122 lines
2.7 KiB
C++
#include "TileLayout.hpp"
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#include <algorithm>
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#include <cmath>
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namespace
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{
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std::vector<Vertex> makeQuad(
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float x0,
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float y0,
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float x1,
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float y1)
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{
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return {
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{{x0, y0}, {0.0f, 0.0f}},
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{{x1, y0}, {1.0f, 0.0f}},
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{{x1, y1}, {1.0f, 1.0f}},
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{{x0, y0}, {0.0f, 0.0f}},
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{{x1, y1}, {1.0f, 1.0f}},
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{{x0, y1}, {0.0f, 1.0f}},
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};
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}
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}
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std::vector<Vertex> makeGridLayout(
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uint32_t cols,
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uint32_t rows,
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float gapX,
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float gapY)
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{
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std::vector<Vertex> vertices;
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vertices.reserve(
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static_cast<size_t>(cols) * rows * 6);
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const float tileW =
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(2.0f - gapX * static_cast<float>(cols - 1)) /
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static_cast<float>(cols);
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const float tileH =
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(2.0f - gapY * static_cast<float>(rows - 1)) /
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static_cast<float>(rows);
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for (uint32_t row = 0; row < rows; ++row)
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{
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for (uint32_t col = 0; col < cols; ++col)
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{
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const float x0 =
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-1.0f +
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static_cast<float>(col) * (tileW + gapX);
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const float y0 =
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-1.0f +
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static_cast<float>(row) * (tileH + gapY);
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const float x1 = x0 + tileW;
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const float y1 = y0 + tileH;
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auto quad = makeQuad(x0, y0, x1, y1);
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vertices.insert(
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vertices.end(),
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quad.begin(),
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quad.end());
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}
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}
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return vertices;
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}
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void updateGridLayout(
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Vertex* vertices,
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uint32_t cols,
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uint32_t rows,
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float gapX,
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float gapY)
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{
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std::vector<Vertex> updated =
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makeGridLayout(cols, rows, gapX, gapY);
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std::copy(
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updated.begin(),
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updated.end(),
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vertices
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);
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}
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void updateUvForAspectRatio(
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Vertex* vertices,
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uint32_t quadIndex,
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float srcAspect,
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float tileAspect)
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{
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Vertex* quad = vertices + quadIndex * 6;
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float uMin = 0.0f;
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float uMax = 1.0f;
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float vMin = 0.0f;
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float vMax = 1.0f;
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if (srcAspect > tileAspect)
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{
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float scale = tileAspect / srcAspect;
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float bar = (1.0f - scale) * 0.5f;
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vMin = bar;
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vMax = 1.0f - bar;
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}
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else if (srcAspect < tileAspect)
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{
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float scale = srcAspect / tileAspect;
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float bar = (1.0f - scale) * 0.5f;
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uMin = bar;
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uMax = 1.0f - bar;
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}
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// Triangle 1: vertices 0-2
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quad[0].uv[0] = uMin; quad[0].uv[1] = vMin;
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quad[1].uv[0] = uMax; quad[1].uv[1] = vMin;
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quad[2].uv[0] = uMax; quad[2].uv[1] = vMax;
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// Triangle 2: vertices 3-5
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quad[3].uv[0] = uMin; quad[3].uv[1] = vMin;
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quad[4].uv[0] = uMax; quad[4].uv[1] = vMax;
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quad[5].uv[0] = uMin; quad[5].uv[1] = vMax;
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}
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